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Sensors presentation-06a
- 1. 1 t h e p a c a . n e tt h e p a c a . n e t Sensors: Getting Engaged!Sensors: Getting Engaged! Event I/O: The Museum Inside-Out/Outside-In 38th Annual MCN Conference Austin, Texas Presented by Abhijit RaoAbhijit Rao Plan A Computing AssociatesPlan A Computing Associates
- 2. 2 t h e p a c a . n e tt h e p a c a . n e t Sensors: Getting Engaged!Sensors: Getting Engaged!
- 3. 3 t h e p a c a . n e tt h e p a c a . n e t Sensors: What are they?Sensors: What are they? “Miniature” devices that capture sensory data React to external stimuli Sensory data incl. heat, humidity, light.... Micro Electro-Mechanical Systems (MEMS) Data transmission is wireless, whereas the Sensing mechanism and power supply are not Sensor: Structure Physical Transducer + Control Logic (Analog + Digital) Abstract Part of a bigger network
- 4. 4 t h e p a c a . n e tt h e p a c a . n e t Sensors: What are they all about?Sensors: What are they all about? Captures sensory data from real physical world Detecting relevant quantities of the data Monitoring and collecting the data Assessing and evaluating collected data Formulating meaningful information ● To be conveyed to the user ● To be stored for future Performing decision making
- 5. 5 t h e p a c a . n e tt h e p a c a . n e t Sensors: Why Museums?Sensors: Why Museums? Traditional Uses User interaction Exhibit Design Ubiquitous Computing “Where technology recedes into the background of our lives.” - Mark Weiser Tetherless Experience Planned Activity Sensing Capability Wow! ● Sensors provide ● Physically unobtrusive, low power, form factor, low maintenance ● New sensing paradigms
- 6. 6 t h e p a c a . n e tt h e p a c a . n e t Sensors: Outlining a FrameworkSensors: Outlining a Framework ExhibitExhibit RemoteRemote ExhibitExhibit Back OfficeBack Office ObserverObserver Link / AgentLink / AgentSensor NetSensor Net Sensor FusionSensor Fusion Sensor ManagementSensor Management db Managementdb Management ...... ServicesServices
- 7. 7 t h e p a c a . n e tt h e p a c a . n e t Sensor: Ecosystem PlayersSensor: Ecosystem Players Multiple devices per square meter ● Mixed data rate requirements ● Varying streaming requirements ● Real-time and tolerate latency Databases ● Static Database – Content, Plan & Rules ● Dynamic Database – User activity context, Sensor data Applications Visitors Sensors Middleware Services ApplicationsDatabase
- 8. 8 t h e p a c a . n e tt h e p a c a . n e t Sensors: Sense ElementSensors: Sense Element TransducerTransducer Physical property to be sensed Detectable signal Also known as Sensor Acceleration measured Accelerometer Sensor Pressure measured Voltage output Pressure sensor Actuator Digital Signal Voice Loudspeaker Actuator Digital Signal Rotary Motion Electrical Motor Transducer type Input (Property of Interest for Sensor) Output (Property of Interest for Actuator) Digital representation (along the axes) Source:Springer.com Author:JFortin
- 9. 9 t h e p a c a . n e tt h e p a c a . n e t Sensors: Typical SensorSensors: Typical Sensor Source:Springer.com Author:JFortin Sense ElementSense Element Physical Property such as heat, light Signal (Charge current)
- 10. 10 t h e p a c a . n e tt h e p a c a . n e t Sensors: Transducer DetailsSensors: Transducer Details Energy Domain Measurand Sense Principle Physical Properties Pressure Piezoresistive, Capacitive Temperature Thermistor, Thermo-mechanical Humidity Resistive, capacitive Motion Properties Position Electro-Magnetic, Contact Sensor Acceleration Vibration (Proof-Mass), Capacitive Gyroscope Capacitive, Electro-Magentic Contact Strain Piezoresistive Vibration Piezoresistive, Sound Presence Tactile/Contact Contact, capacitive Proximity Hall effect, Magnetic, RF Identification ID Fingerprint, data stored, retinal scan Source: Silicondesigns.com
- 11. 11 t h e p a c a . n e tt h e p a c a . n e t Sensors: SMART SensorSensors: SMART Sensor Provides extra functions beyond just the correct representation of the sensed physical quantity “Moving the intelligence” closer to the point of measurement Control Logic Virtual Sensor Sense Element (MEMS) Application Algorithm Communication Interface Analog-to-Digital Conversion Signal Conditioning Digital Signal Processing User Interface buttons/led Storage (Threshold / Calibration) Physical Input Base StationBase Station HostHost SMART Sensor SMART Sensor S.M.A.R.T. Self- Monitoring, Analysis, and Reporting Technology
- 12. 12 t h e p a c a . n e tt h e p a c a . n e t Sensors: Virtual SensorSensors: Virtual Sensor Virtual SensorVirtual Sensor Source:sparkfun.com Control Logic Virtual Sensor Sensor Element Application Algorithm Communication Interface Analog-to- Digital Conversion Signal Conditioni ng Digital Signal Processing User Interface buttons/led Storage (Threshold / Calibration) Base StationBase Station HostHost Smart Sensor Smart Sensor
- 13. 13 t h e p a c a . n e tt h e p a c a . n e t Sensors: Wireless ConnectivitySensors: Wireless Connectivity Source:laboratoryequipment.com
- 14. 14 t h e p a c a . n e tt h e p a c a . n e t Sensors: Power & NetworkingSensors: Power & Networking Source:laboratoryequipment.com Source:techbriefs.com
- 15. 15 t h e p a c a . n e tt h e p a c a . n e t Sensors: Key DriversSensors: Key Drivers Drivers Today's sensor future Scale Micro Nano Power consumption long life (> 2 years) energy harvesting Improving Cost & Yield Standardization efforts in Wireless Networking Cheaper Efficient Tinier Processing Logic Quick Integration Methods Development of low power radio technologies Advances in low-power embedded micro-controllers
- 16. 16 t h e p a c a . n e tt h e p a c a . n e t Sensors: System DesignSensors: System Design Wireless Networking Middleware Services Data Management Sensory User Interaction (SUI) Approach Identify the use case scenarios List sense element and energy domain details Calculate anticipated workload Identify the sensor network algorithms Perform the Sensor System Design in conjunction with the Exhibit Design
- 17. 17 t h e p a c a . n e tt h e p a c a . n e t Sensor: Identifying a SensorSensor: Identifying a Sensor Identify the measurand Energy Domain Usage Pattern Bandwidth and other resource requirements Characteristics Power consumption Network support Form factor Volume of sensors to deploy and use Vendor selection Minimum Quantity requirements Lead time
- 18. 18 t h e p a c a . n e tt h e p a c a . n e t Sensors: Technology restrictionsSensors: Technology restrictions Size and packaging Energy efficiency (Power constraints) Data rates for the wireless data transfer High data rates (Audio/Video) / Streaming Low data rates (spatial sensors, environment sensing) Fine grained estimation and tracking of location and orientation of large number of objects that are being sensed Quality of Service needs
- 19. 19 t h e p a c a . n e tt h e p a c a . n e t Sensors: System ExampleSensors: System Example Sensors - Lightweight Location & Orientation Identification Network Agent – Conduit for the sensors Master – Act upon sensor data Location & Orientation Identification Object Tracking Spatial Configuration of multiple users and objects
- 20. 20 t h e p a c a . n e tt h e p a c a . n e t Agent Host Sensors: Outlining a FrameworkSensors: Outlining a Framework Sensor 1 Sensor 2 Sensor 3 ComputerComputer WebWeb Exploration & Learning Plan Content Management Exploration & Learning Interaction HandheldHandheld System Hardware Software App stackSensors
- 21. 21 t h e p a c a . n e tt h e p a c a . n e t Sensors are a mature market!Sensors are a mature market! Using those sensors in a large scale, inUsing those sensors in a large scale, in Museums, will have aMuseums, will have a rrevolutionary effect in userevolutionary effect in user experience.experience. Sensory User Interaction is here to stay!Sensory User Interaction is here to stay! If there is sufficient interest we can explore opening a SIG under MCNIf there is sufficient interest we can explore opening a SIG under MCN To receive these slides, please send an email to abhi@thepaca.net Sensor: Getting Engaged!Sensor: Getting Engaged!
- 22. 22 t h e p a c a . n e tt h e p a c a . n e t Thank you!Thank you!
- 23. 23 t h e p a c a . n e tt h e p a c a . n e t BackupBackup
- 24. 24 t h e p a c a . n e tt h e p a c a . n e t Sensors: Experience RealmsSensors: Experience Realms Sensors can enhance the all experience realms
- 25. 25 t h e p a c a . n e tt h e p a c a . n e t Sensor: Sample applicationsSensor: Sample applications Wireless network of toys Learning individualized to the participant / each child Unobtrusive evaluation of the learning process Hidden in the infrastructure (walls, chairs, ...) Music toys (MIT Media Lab's Toy Symphony) Heavy on gestures and tactile in nature Embed sensors for touch, pressure .. in toys and exhibit objects and detect their manipulation
- 26. 26 t h e p a c a . n e tt h e p a c a . n e t Sensors: Compare to a typical ComputingSensors: Compare to a typical Computing SystemSystem Ad-hoc and Distributed structure Likely to be large scale yet sparse in density Unreliability due to nature of the link Restricted system resources, Power management Overcome by huge amount data that gets collected (redundancy) Physical stimulus and reactionary in nature Predominantly unstructured and asynchronous Diversity of data types with large dynamic range of rate, latency, processing requirements
- 27. 27 t h e p a c a . n e tt h e p a c a . n e t Sensors: Transducer PropertiesSensors: Transducer Properties Physical Properties Used to measure Pressure, temperature, Humidity... Motion Properties Used to measure Acceleration, Position, Angular velocity, Direction Contact Properties Used to measure Vibration, Slip, Strain Presence Used to measure Tactile, Contact, Proximity, Motion, Light Identification Used to measure ID Data, Retinal, Voice, ...
- 28. 28 t h e p a c a . n e tt h e p a c a . n e t Sensors: Sense Element BasicsSensors: Sense Element Basics Energy Domain Characteristic Transduction Principle Mechanical Thermal Optical Rely on direct Physical contact Capacitive Sensors as in Touch Sensors Piezoelectric effect as in balls that lit when bounced Electromagnetic / Magnetic Useful for detecting proximity events Eddy-current sensors allows bigger sensing range and bigger probe spot size RFID use power in the interrogating signals to send back small amounts of data Measure temperature or heat flux Thermoresistive effect exploits resistance of a conductor/semiconductor changes with temperature Thermocouples sensor based on current flows between two materials are joined together and one is hotter than the other. It is less expensive and is very reliable Resonant Temperature sensors are expensive and very high accuracy. convert light to various quantities Photoelectric effect measures the flow of electrons based on incident light Source:lionprecision.com Source:analog.com Source:eetimes.com
- 29. 29 t h e p a c a . n e tt h e p a c a . n e t Sensors: Other Sensor ElementsSensors: Other Sensor Elements Energy Domain Description / Uses Chemical Biological Medical Diagnostic, detecting Pesticides Chemiresistors Biosensors EM spectrum Radar / Lidar, GPS Acoustic Acoustic Wave Interact with matter of all types – Used in sensing pollutions causing gases Implemented with an array of chemical sensors, interpreted using a pattern-recognition algorithm – to sense a variety of chemicals. Used in Contamination assessment Metal-Oxide Gas sensors relies on adsoprtion of gases onto certain semiconductors changes their resistivity. Used in smoke detectors Sensing depends upon selectivity of biomolecular reactions such as molecular binding sites – detect property changes mass, resistance, spectral reading Sound as the sensing medium – detecting fluid leakages and earthquakes Employs two sets of “fingers” one to generate the surface Acoustic Wave and the other to detect the changes. Very versatile in its applications. Source:sandia.gov Source:sensormag.com
- 30. 30 t h e p a c a . n e tt h e p a c a . n e t Sensors: Mapping a Smart SensorSensors: Mapping a Smart Sensor Control Logic Virtual Sensor Sensor Element Application Algorithm Communication Interface Analog-to-Digital Conversion Signal Conditioning Digital Signal Processing User Interface buttons/led Storage (Threshold / Calibration) Base StationBase Station HostHost Smart Sensor Smart Sensor
- 31. 31 t h e p a c a . n e tt h e p a c a . n e t Sensors: MEMS Sensor SoCSensors: MEMS Sensor SoC Control Logic Virtual Sensor Sensor Element Application Algorithm Communication Interface Analog-to-Digital Conversion Signal Conditioning Digital Signal Processing User Interface buttons/led Storage (Threshold / Calibration) Base StationBase Station HostHost Smart Sensor Smart Sensor Source: invensense.com
- 32. 32 t h e p a c a . n e tt h e p a c a . n e t Sensors: Form factorSensors: Form factor Standalone Integrated onto a PCB Source:monnit.com Source:kcftech.com Source:freescale.com
- 33. 33 t h e p a c a . n e tt h e p a c a . n e t Sensors: Adoption TodaySensors: Adoption Today Building industry, Green evolution, Transportation, Home automation, ... Importance indicated by IEEE driven standards in this space Driven by affordability and ease of use Efficient and low cost connectivity methods Classified solutions based on data rates
- 34. 34 t h e p a c a . n e tt h e p a c a . n e t BackupBackup
- 35. 35 t h e p a c a . n e tt h e p a c a . n e t Sensor: ChallengesSensor: Challenges Power Lack of ruggedness Steep learning curve
- 36. 36 t h e p a c a . n e tt h e p a c a . n e t Actuator: Display TechnologyActuator: Display Technology Source: flexlighing.com Source: holografika.com Source: microvision.com Source: mirasoldisplays.com
- 37. 37 t h e p a c a . n e tt h e p a c a . n e t Actuator: Tactile FeedbackActuator: Tactile Feedback Source: densitron.comSource: densitron.com Source: immersion.com
- 38. 38 t h e p a c a . n e tt h e p a c a . n e t Actuator and Sensor Combined:Actuator and Sensor Combined: Touchable 3D DisplayTouchable 3D Display Source: docomo
- 39. 39 t h e p a c a . n e tt h e p a c a . n e t ReferencesReferences Weiser, Mark – The Computer for the 21st Century Scientific American Vol 265 p 66-75 http://www.ubiq.com/hypertext/weiser/SciAmDraft3.html Smart Kindergarten: Sensor-based Wireless networks for Smart Developmental Problem- solving environments - ACM ISBN 1-58113- 422-3/01/07
Editor's Notes
- There has been this surge in Wireless Sensors – it is a reasonable mature market – it is not anymore confined to the walls of an R& D Lab. We will look at some of the detail including the internals of a sensor, the structure etc,. the emerging uses, what has propelled their growth and how to use them. We take a look couple of potential applications and the framework. Other than sensors- affordable computing systems, mobile devices and wireless technologies are fueling the growth – new possibilities in exploring and learning. Sensors will drive the next surge of innovation in Museums. With the advances in semiconductor technology, various sensors such as temperature, motion sensing, pressure, humidity, compass, touch and proximity are being made affordable and easy to use. Sensors will allow the museum to present the visitor with a whole new world of interactivity / engagement. Various forms of Wireless connectivity available today only make it more convenient to design and manage. This lecture will provide an introduction to the digital sensors- their characteristics and then the selection process. Also covered will be the common requirements to be considered in selecting wireless connectivity techniques, followed by a discussion of the approaches and likely challenges to integrating sensors into a comprehensive and useful system.
- So are we looking at Sensors just because those are cool things? No I do not think so – Sensors do have wide applicability and it is more than the “cool factor” - sensors are likely to cause paradigm shift. There is small use of Sensors – but what I think will happened is much bigger acceptance in the usage sensors. Traditionally sensors have been used in museums to measure the ambient conditions such as light and humidity for preservation purposes. The digital IC based sensors of today provide data that can be monitored remotely with an automated system configured to respond appropriately. The automated system can also log data to help in planning and maintenance.
- Sensors are much more accurate beyond; often beyond human levels of cognition – huge mtbf unlike human...
- Sensory data comes from multiple sensors of different modalities/requirements often in distributed locations It is a pipeline – one stage after the other
- Combining Sensors with traditional computing systems – hand held, PDA, Computer systems can enhance and extend the fun in learning. Smart environments instrumented with sensor-and-wireless-enhanced objects would be able to sense events and conditions about people/objects (basically the participants) and act upon the sensed information or use it as context when responding to queries and commands. What you see here is “sensing + wireless communication + embedded processing” Ubiquitous Computing term coined by mark Weiser – he identified it as the thirdwave in Computing
- In here the sensor talks to a Link / Agent – it is also conceivable that Sensor Net elements can be designed/implemented in such a way that the data from one sensor will hop to the adjacent sensor until the data reaches the main LAN.
- Measurand- A physical quantity, property, or condition which is measured. A transducer is a device that converts one type of energy to another. Can either be a Sensor or Actuator. Sensor detect energy in one form and report in another form. Such as Pressure, Temperature, Airbag,... Actuator receives energy and generates action such as loudspeaker, electric motor, .. (electromechanical output devices are generically called actuators) For high precision Capacitive sensors – and longer range laser or optical based sensors Eddy-Current sensor tolerance of dirty environment also used for position measurement/sensing as in the disk drives
- Electric current depending on the context, a flow of electric charge (a phenomenon) or the rate of flow of electric charge (a quantity). Pressure Sensor
- SMART
- Virtual sensor estimates the properties in conjunction with physical sensors. Virtual sensors manage drifts, calibration
- Most wireless sensors, particularly those based on IEEE 802.15.4 or 900 MHz radios, are designed to use power very conservatively. 900MHz can propagate further (less attenuation), whereas 2.4GHz based protocols handle obstruction better (900MHz ISM in NA, Aus. & Israel) 802.15.4 standardizes the MAC and PHY – the upper stacks (as in WirelessHART and ZigBee) are not compatible. (PHY 868MHz in Europe + 900Mhz elsewhere + 2.4GHz) Wireless Sensors – the required data rate, low energy consumption and low cost are paramount Wi-Fi/802.11 – Security, QoS and Bandwidth are important
- In a cluster tree network, each node connects to a node higher in the tree until the data reaches the gateway. This simple algorithm may be used with any wireless radio technology. Finally, in a mesh network, nodes can connect to multiple other nodes in the system and pass data through the most reliable path available. If one link goes down, affected nodes can pass data through another path to reach the gateway. Most IEEE 802.15.4-based devices employ some type of mesh network topology, because of this self-healing effect. In Star all sensors transmit directly to the central data collection point. Mesh network best over large distances, harsh RF environments, to avoid 1 single point of failure
- Advances in the computing technology promotes the “sensing and act” on the physical environment suggesting the “person to physical world” connection is closer and achievable than ever.
- Having sensors and wireless connectivity is only the first part of the puzzle – the widdleware services is essential for a successful SUI
- QoS - it maybe OK to miss temperature samples but not necessarily that of the orientation sensor
- Generate information such a Kid A is in the corner near Pyramid A
- ELP – manages the purpose of the tool or the exhibit ... such as (i) Weather Station – it will be weather science study that is adjusted to the age group (ii) Earth navigator – it will be region & climate study l CM – Manage local data, share if necessary data with similar systems (Database Mgmt) ELI – It handles the UI and rules management To summarize the three key challenges are to be handled are - creating networked sensing approaches - networking protocols optimized for large scale and high density sensor presence - processing and analysis of data generated by all these sensors
- Ubiquitous Computing "that which informs but doesn't demand our focus or attention." Problem solving in nature – unstructured because of the kind of data that is collected to make sense out of it. And then react to it in realtime in a context sensitive fashion Toys of Tomorrow and Music Toys programs at MIT's Media Lab
- For high precision Capacitive sensors – and longer range laser or optical based sensors Eddy-Current sensor tolerance of dirty environment also used for position measurement/sensing as in the disk drives Security aspects are key to while designing proximity sensors. Hall effect is another type of electromagnetic sensor - production of a voltage in a current-carrying semiconductor in the presence of a magnetic field. Thermocouples based on Seebeck effect. Resonant-Temperature sensor based on the property of SiO2 to exhibit a change in resonant frequency depending on temperature change. Optical transducers can be optimized for different frequencies of light – visible and non-visible so that you can have infrared detectors, ultraviolet detectors and so on.
- Chemical Transducers used in environmental monitoring Chemiresistors are expensive because of the specialized nature – nevertheless it is very accurate. It uses electrodes that are coated with specialized chemical agents that change their resistance when exposed to certain challenge agents. Array of biosensors are put together for an Electronic nose. Em Spectrum sensors used in autonomous vehicle navigation. It requires expensive DSP techniques including edge detection, segmentation, motion analysis etc., Acoustic sensors also uses Doppler techniques for the measurement of velocities Acoustic Wave Sensors uses the changes to the characteristic of the propagation path effect the velocity and/or amplitude of of the acoustic wave – these sensors are often used in conjunction with materials that demonstrate Piezoelectric effect. It I perhaps the most versatile of sensors – because it has been used to sense many physical properties
- Predominantly used as spatially distributed autonomous sensors to monitor physical environment conditions.
- Sensors when coupled with the growth in display technologies and tactile feedback technologies will open a wavefront of innovation in user interaction and exhibit design.
- When the user touches the screen, a position signal is sent to the microprocessor. The host application interprets this position and commands the lightweight TouchSense player, embedded on the processor, to play a specified tactile effect, such as the perception of a button press. Haptics is a catchall term for sub-types including Tactile (the sense of pressure applied through skin), kinaestehtic (motion of the body),